Every 15 minutes new SUDOKU puzzle!

Sudoku is a logic-based placement puzzle, also known as Number Place in the United States. The aim of the canonical puzzle is to enter a numeral from 1 through 9 in each cell of a 9×9 grid made up of 3×3 subgrids, starting with various numerals given in some cells. Each row, column and region must contain only one instance of each numeral. Completing the puzzle requires patience and logical ability.